Characterization of Environmental Dust in the Dammam Area and Mud After-Effects on Bisphenol-A Polycarbonate Sheets

Owing to recent climate changes, dust storms are increasingly common, particularly in the Middle East region. Dust accumulation and subsequent mud formation on solid surfaces in humid environments typically have adverse effects on surface properties such as optical transmittance, surface texture, and microhardness. This is usually because the mud, which contains alkaline and ionic species, adheres strongly to the surface, often through chemical bonds, and is therefore difficult to remove. In this study, environmental dust and the after-effects of mud formed on a polycarbonate sheet, which is commonly used as a protective glass in photovoltaic cells. Ionic compounds (OH−) are shown to significantly affect the optical, mechanical, and textural characteristics of the polycarbonate surface, and to increase the adhesion work required to remove the dry mud from the polycarbonate surface upon drying. Such ability to modify characteristics of the polycarbonate surface could address the dust/mud-related limitations of superhydrophobic surfaces

Adhesion characteristics of solution treated environmental dust

Environmental dust is modified towards self-cleaning applications under the gravitational influence. Dust particles are collected in the local area of Dammam in Saudi Arabia and they are treated with a dilute hydrofluoric acid solution. The changes in chemical and adhesion characteristics of the dust particles prior and after the solution treatment are analyzed. Force of adhesion and work required to remove dust from hydrophobic and hydrophilic glass surfaces are assessed, separately, for solution treated and collected dust. We show that aqueous hydrofluoric acid solution treatment modifies some dust components while causing the formation of submicron cracks and nano/submicron porous/pillars like textures on the dust particles. The texture generated on dust surfaces after the solution treatment has a great influence on dust adhesion characteristics. Hence, the solution treated dust particles result in lower adhesion on hydrophobic and hydrophilic glass surfaces as compared to that of untreated dust. The gravitational force enables to remove solution treated dust from inclined glass surfaces, which becomes more apparent for hydrophobic surfaces.The study was supported by King Fahd University of Petroleum and Minerals (KFUPM) through Projects# IN171001 and King Abdullah City for Atomic and Renewable Energy (K.A.CARE) to accomplish this work

Additive manufacturing of Ti-alloy: Thermal analysis and assessment of properties

In this study, 3D printing of Ti6Al4V alloy is realized and the characteristics of the printed layer are examined. The morphological structures and metallurgical changes in the printed layer are assessed. Temperature and stress fields are simulated in line with the experimental conditions. Since the air gaps are present in between the loose alloy powders prior to the printing, the effective properties incorporating the air fraction are determined and the effective properties are used in the simulations. Thermal conductivity of the loose alloy powders with the presence of air gaps is determined by incorporating the virtual experimental technique. It is found that the printed layer is free from micro-cracks and large scale asperities; however, some small pores sites are observed because of the release of air around the loose powders during the printing. Microhardness of the printed surface is higher in the top surface of the printed layer than that of as-received solid alloy. In addition, the friction coefficient of the printed surface remains lower than that of the conventionally produced solid surface. The columnar structures are formed in the mid-section of the printed layer and slanted grains are developed in the region of the top and the bottom surface of the printed layer.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors acknowledge the financial support of King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia, Gazi University and TAI (SAYP Project DDKIG1) in Turkey and King Abdullah City for Atomic and Renewable Energy (K.A.CARE) to accomplish this work

Laser Drilling: Practical Applications

This book introduces laser drilling processes including modelling, quality assessment of drilled holes, and laser drilling applications. It provides insights into the laser drilling process and the relation among the drilling parameters pertinent to improved end product quality. This book is written for engineers and scientists working on laser machining, particularly laser drilling

<span style="font-size:11.0pt;font-family:"Calibri","sans-serif"; mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman";mso-ansi-language:EN-US;mso-fareast-language: EN-US;mso-bidi-language:AR-SA">Cloth Cutting by CO₂ Laser</span>

143-145A number of cloth samples from the Aquascutum range were tested on a CO2 laser to determine the laser power required to cut at useful speeds. The results showed that it would be possible to cut most of the material at a speed of 400 ft/min with a steady laser power of 200 W.</span

MEASUREMENT OF TEMPERATURE-DEPENDENT REFLECTIVITY OF CU AND AL IN THE RANGE 30-1000-DEGREES-C

In the CO2 laser cutting process it is important to predict the absorption mechanism during laser-workpiece interaction, since the form of the dependence of absorption on temperature greatly affects the form of the resulting temperature profile in the material. In order to be able to use any of the theoretical models for absorption with any degree of confidence, it appears necessary to obtain experimental data on the subject. Consequently an experiment to determine the variation of absorption with temperature is necessary. In the present study, a reflectivity method is employed to measure the temperature-dependent reflection coefficient experimentally. The results obtained from the experiment for aluminium and copper samples are then compared with the theoretical results. In the analysis, high-temperature surface oxidation is also included